mirror of https://github.com/docker/cli.git
52 lines
1.6 KiB
Go
52 lines
1.6 KiB
Go
package wclayer
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import (
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"context"
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"syscall"
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"github.com/Microsoft/hcsshim/internal/hcserror"
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"github.com/Microsoft/hcsshim/internal/log"
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"github.com/Microsoft/hcsshim/internal/oc"
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"go.opencensus.io/trace"
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)
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// GetLayerMountPath will look for a mounted layer with the given path and return
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// the path at which that layer can be accessed. This path may be a volume path
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// if the layer is a mounted read-write layer, otherwise it is expected to be the
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// folder path at which the layer is stored.
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func GetLayerMountPath(ctx context.Context, path string) (_ string, err error) {
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title := "hcsshim::GetLayerMountPath"
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ctx, span := trace.StartSpan(ctx, title)
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defer span.End()
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defer func() { oc.SetSpanStatus(span, err) }()
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span.AddAttributes(trace.StringAttribute("path", path))
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var mountPathLength uintptr
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mountPathLength = 0
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// Call the procedure itself.
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log.G(ctx).Debug("Calling proc (1)")
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err = getLayerMountPath(&stdDriverInfo, path, &mountPathLength, nil)
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if err != nil {
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return "", hcserror.New(err, title+" - failed", "(first call)")
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}
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// Allocate a mount path of the returned length.
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if mountPathLength == 0 {
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return "", nil
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}
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mountPathp := make([]uint16, mountPathLength)
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mountPathp[0] = 0
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// Call the procedure again
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log.G(ctx).Debug("Calling proc (2)")
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err = getLayerMountPath(&stdDriverInfo, path, &mountPathLength, &mountPathp[0])
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if err != nil {
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return "", hcserror.New(err, title+" - failed", "(second call)")
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}
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mountPath := syscall.UTF16ToString(mountPathp[0:])
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span.AddAttributes(trace.StringAttribute("mountPath", mountPath))
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return mountPath, nil
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}
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